Method and system for wirelessly and passively measuring temperature and devices forming the system

ABSTRACT

The present disclosure provides a method and a system for wirelessly and passively measuring temperature and devices forming the system. The method includes: receiving an energy feedback radio frequency (RF) signal by a temperature measuring end; converting the energy feedback RF signal into electric energy and storing the electric energy; and starting the temperature measuring end after obtaining the electric energy, and transmitting a RF signal under the current temperature to a terminal, and calculating the current temperature through the terminal. The method, the system and the devices forming the system provided in the present disclosure are capable of activating the crystal oscillator or the ceramic oscillator wirelessly and passively, therefore, the method, the system and the devices can be used to wirelessly and passively measure temperature, which is convenient.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Divisional Application of U.S. applicationSer. No. 15/193,191 filed on Jun. 27, 2016, which a ContinuationApplication of PCT application No. PCT/CN2014/094864 filed on Dec. 24,2014, which claims the benefit of Chinese Patent Application No.201310728107.3 filed on Dec. 25, 2013, the contents of which are herebyincorporated by reference.

FIELD OF THE INVENTION

The present disclosure generally relates to the field of temperaturemeasurement and, more particularly, relates to a method and a system forwirelessly and passively measuring temperature and devices forming thesystem.

BACKGROUND

Main human body features include body temperature, blood pressure,pulse, respiration, etc. During these human body features, bodytemperature is a very important physiological signal which forms animportant part of the measuring and monitoring of the medical care work.The measuring accuracy in medical level is 0.2° C. Nowadays, the mercurythermometer is still used as the medical temperature measuring tool.However, the mercury thermometer has hidden dangers in safety andenvironment pollution. The hidden safety danger includes cross-infectionand being cut by the glass when the glass of the mercury thermometerbreaks. The hidden danger in environment pollution may arise when themercury thermometer breaks since the mercury is a toxic substance.Moreover, it takes long time to measure the temperature using themercury thermometer and it is troublesome to read the data, whichaffects the work efficiency.

Since the technology of quartz crystal oscillator has the advantagesincluding strong stability and rapid measurement speed, the technologyof quartz crystal oscillator can be used to measure temperature byreplacing the mercury thermometer. However, at present, during thetemperature measurement, extra electric energy needs to be provided toactivate the quartz crystal oscillator, resulting in the complex usageof the quartz crystal oscillator. Thus, it is inconvenient for the userto use the technology of quartz crystal oscillator.

BRIEF SUMMARY OF THE DISCLOSURE

The main purpose of the present disclosure is to provide a method and asystem for wirelessly and passively measuring temperature and devicesforming the system, which can conveniently and rapidly measuretemperature.

One aspect of the present disclosure provides a method for wirelesslyand passively measuring temperature, including:

receiving an energy feedback radio frequency (RF) signal by atemperature measuring end;

converting the energy feedback RF signal into electric energy andstoring the electric energy; and

starting the temperature measuring end after obtaining the electricenergy, transmitting a RF signal under the current temperature to aterminal, and calculating the current temperature through the terminal.

Preferably, the temperature measuring end includes a crystal oscillatorcircuit; the crystal oscillator circuit starts after obtaining theelectric energy, and transmits the RF signal under the currenttemperature.

Preferably, the step of converting the energy feedback RF signal intoelectric energy and storing the electric energy includes:

receiving the energy feedback RF signal through a RF receiving circuitby the temperature measuring end, and storing the energy of the feedbackRF signal into a storage capacitor by the RF receiving circuit.

Preferably, after the step of starting the temperature measuring endafter obtaining the electric energy, and transmitting a RF signal underthe current temperature to a terminal, and calculating the currenttemperature through the terminal, the method further includes:

sending the calculated current temperature to a remote terminal throughnetwork.

One aspect of the present disclosure provides a wireless and passivetemperature sensing device, including a RF receiving circuit, a storagecapacitor, and a crystal oscillator circuit; the RF receiving circuitreceives an energy feedback RF signal from an energy feedback device,and converts the energy feedback signal into electric energy; theelectric energy is stored into the storage capacitor; and after avoltage of the storage capacitor reaches a suitable level, the crystaloscillator is started to transmit a RF signal under the currenttemperature to an external receiving and processing device.

Preferably, the wireless and passive temperature sensing device furtherincludes a first house; the RF receiving circuit, the storage capacitor,and the crystal oscillator circuit are configured inside the firsthouse; one side of the first house corresponding to the crystaloscillator is made of thermal conductive material; or, one side of thefirst house corresponding to the crystal oscillator forms an openingthrough which the crystal oscillator circuit protrudes from the side ofthe first house.

Preferably, the wireless and passive temperature sensing device furtherincludes a connection structure; the connection structure includes atleast one protrusion configured on a peripheral side of the first houseand a through hole formed on each of the at least one protrusion; or,the connection structure includes a Velcro configured on the firsthouse; or, the connection structure includes a locking device configuredon the first house.

One aspect of the present disclosure provides an energy feedback device,including a first temperature compensation crystal oscillator and a RFpower amplifier; a RF signal from the first temperature compensationcrystal oscillator is amplified by the RF power amplifier and is furthertransmit to a wireless and passive temperature sensing device.

One aspect of the present disclosure provides a receiving and processingdevice, comprising a temperature compensation crystal oscillator, a RFreceiving amplifier, and a signal processor; the RF receiving amplifierreceives a RF signal under the current temperature transmit by awireless and passive temperature sensing device and outputs the RFsignal into the signal processor; and the signal processor calculatesthe current temperature according to an inherent frequency of thetemperature compensation crystal oscillator and the received RF signalunder the current temperature.

Preferably, the receiving and processing device further includes anetwork unit connected to the signal processor for receiving andtransmitting data through network.

One aspect of the present disclosure provides an energy feedbackreceiving and processing device, including a temperature compensationcrystal oscillator, a RF power amplifier, a RF receiving amplifier, anda signal processor; a RF signal from the temperature compensationcrystal oscillator is amplified by the RF power amplifier and is furthertransmit to a wireless and passive temperature sensing device; the RFreceiving amplifier receives the RF signal under the current temperaturefrom the wireless and passive temperature sensing device and outputs theRF signal to the signal processor; and the signal processor calculatesthe current temperature according to an inherent frequency of thetemperature compensation crystal oscillator and the received RF signalunder the current temperature.

Preferably, the energy feedback receiving and processing device furtherincludes a second house; the temperature compensation crystaloscillator, the RF power amplifier, the RF receiving amplifier, and thesignal processor are configured in the second house.

Preferably, the energy feedback receiving and processing device furtherincludes a network unit connected to the signal processor for receivingand transmitting data through network.

One aspect of the present disclosure provides a system for wirelesslyand passively measuring temperature, comprising a wireless and passivetemperature sensing device, an energy feedback device, and a receivingand processing device;

the energy feedback device includes a temperature compensation crystaloscillator and a RF power amplifier, and a RF signal from thetemperature compensation crystal oscillator is amplified by the RF poweramplifier and is further transmit to the wireless and passivetemperature sensing device;

the wireless and passive temperature sensing device includes a RFreceiving circuit, a storage capacitor, and a crystal oscillatorcircuit; the RF receiving circuit receives an energy feedback RF signalfrom the energy feedback device; energy of the RF signal is stored intothe storage capacitor; after the voltage of the storage capacitorreaches a suitable level, the crystal oscillator circuit is activated totransmit the RF signal under the current temperature from the crystaloscillator circuit to the receiving and processing device;

the receiving and processing device includes a temperature compensationcrystal oscillator, a RF receiving amplifier, and a signal processor;the RF receiving amplifier receives the RF signal under the currenttemperature from the wireless and passive temperature sensing device andoutputs the RF signal into the signal processor; and the signalprocessor calculates the current temperature according to an inherentfrequency of the second temperature compensation crystal oscillator andthe received RF signal under the current temperature.

Preferably, the energy feedback device and the receiving and processingdevice share one temperature compensation crystal oscillator.

Preferably, the wireless and passive temperature sensing device includesa first house; the RF receiving circuit, the storage capacitor, and thecrystal oscillator circuit are configured in the first house; and oneside of the house corresponding to the crystal oscillator circuit ismade of thermal conductive material; or, one side of the first houseforms an opening through which the crystal oscillator protrudes from theside of the house.

Preferably, the receiving and processing device further includes anetwork unit connected to the signal processor for receiving andtransmitting data through network.

Compared with the current temperature measuring method which needs to beconnected to an electric wire for providing electric energy to activatethe crystal oscillator and is troublesome, the method and the system anddevices forming the system for wirelessly and passively measuringtemperature uses are capable of activating the crystal oscillator or theceramic oscillator wirelessly and passively, therefore, the method, thesystem and the devices can be used to wirelessly and passively measuretemperature, which is convenient. Also, the method, the system, and thedevices can be applied in medical filed by replacing the mercurythermometer without the danger in cross infection, breaking of theglass, and environment pollution, as well as improve the workingefficiency of the medical care personnel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a flow chart of a method for wirelessly and passivelymeasuring temperature consistent with disclosed embodiments;

FIG. 2 illustrates a schematic diagram of a wireless and passivetemperature sensing device consistent with disclosed embodiments;

FIG. 3 illustrates a schematic view of a first house of the device ofFIG. 2;

FIG. 4 illustrate a schematic diagram of an energy feedback deviceconsistent with disclosed embodiments;

FIG. 5 illustrates a schematic diagram of a receiving and processingdevice consistent with disclosed embodiments;

FIG. 6 illustrates a schematic diagram of an energy feedback receivingand processing device consistent with disclosed embodiments;

FIG. 7 illustrates a schematic diagram of a system for wirelessly andpassively measuring temperature consistent with a first embodiment; and

FIG. 8 illustrates a schematic diagram of a system for wirelessly andpassively measuring temperature consistent with another embodiment.

The realization of the object, features, and advantages of the presentdisclosure are given in further detail in combination with theembodiments with reference to the accompanying drawings.

DETAILED DESCRIPTION

It should be understood that the embodiments described herein are onlyused to explain the present disclosure rather than to limit the presentdisclosure.

Referring to FIG. 1, a method for wirelessly and passively measuringtemperature according an embodiment is provided. The method includessteps as followed.

Step S1, a temperature measuring end receives an energy feedback radiofrequency (RF) signal. The temperature measuring end can be a wirelessand passive temperature sensing device including a crystal oscillatorcircuit having a crystal oscillator. An oscillating frequency of thecrystal oscillator depends on the resonant frequency of the crystal.Since the change of the resonant frequency is only affected by thetemperature of the crystal and the crystal itself, therefore, if thecrystal oscillator is used for transmitting the RF signal, the RF signalcorresponds to the current temperature. The temperature sensing speed ofthe crystal oscillator is rapid, and the frequency of the RF signal ofthe crystal oscillator is decided by the temperature and the oscillatoritself, thus, the temperature can be rapidly and accurately measured byusing the crystal oscillator. In some embodiments, the crystaloscillator circuit can be a quartz crystal oscillator circuit or aceramic crystal oscillator circuit.

Step S2, converting the energy feedback RF signal into electric energyand storing the electric energy. The temperature measuring end receivesthe energy feedback RF signal through a RF receiving circuit whichconverts the energy feedback RF signal into electric energy. Theelectric energy is stored into a storage capacitor until the voltage ofthe storage capacitor goes up to a suitable level capable of providingworking electric energy for the crystal oscillator circuit. The suitablelevel of the voltage of the storage capacitor means that, the voltage ofthe storage capacitor is enough for the crystal oscillator to work for apredetermined period. When the voltage of the storage capacitor is lessthan the voltage needed by the crystal oscillator circuit, the crystaloscillator circuit stops working. In this way, the temperature measuringend can work normally without being connected to an electric wire or apower supply cell. This ensures the temperature measuring end to besmall and portable, and thus the temperature measuring end can be placedat the to-be-measured point at any time without affecting the situationof the to-be-measured point. For example, body temperature can bemeasured by placing the temperature measuring end inside the underwearof the user without affecting daily life of the user. Based on this, thetemperature measuring end can be used passively, which allows the userto neglect the existence of the temperature measuring end and thetemperature to be measured easily. The RF signal is generally transmitby the energy feedback device. The energy feedback device includes afirst temperature compensation crystal oscillator and a RF poweramplifier. The RF signal from the temperature compensation crystaloscillator is amplified by the RF power amplifier and then is transmitto the wireless and passive temperature sensing device.

Step S3, the temperature measuring device starts after obtaining theelectric energy and transmits the RF signal under the currenttemperature to a terminal, and the current temperature is calculated bythe terminal. The terminal can be an electric device which is capable ofreceiving the RF signal under the current temperature and calculatingthe current temperature based on the RF signal. The terminal istypically a receiving and processing device, including a temperaturecompensation crystal oscillator, a RF receiving amplifier, and a signalprocessor. The RF receiving amplifier receives the RF signal under thecurrent temperature sent from the wireless and passive temperaturesensing device and outputs the signal to the signal processor. Thesignal processor calculates the current temperature according to theinherent frequency of the temperature compensation crystal oscillatorand the received RF signal.

In an embodiment, the method for wirelessly and passively measuringtemperature further includes step S4: the terminal sends the calculatedcurrent temperature to a remote terminal through network. Through thisstep, the calculated temperature can be sent to different users whichare not present during the measurement process. For example, in thehospital, the nurse or the patient can send the measured temperature tothe doctor through network, allowing the doctor to obtain the bodytemperature in time, which is convenient and rapid.

The method for wirelessly and passively measuring temperature providedin the disclosure is capable of wirelessly activating the crystaloscillator or ceramic oscillator by using the converting method from theRF signal to the electric energy, and thus capable of activating thecrystal oscillator or the ceramic oscillator wirelessly and passively.Therefore, the method can be used conveniently and can be applied inmedical filed. The accuracy of the device applying the method can reach0.2° C. and thus is capable of replacing the mercury thermometer withoutthe danger in cross infection, breaking of the glass, and environmentpollution. Meanwhile, the device can improve the working efficiency ofthe medical care personnel.

Referring to FIG. 2, a wireless and passive temperature sensing deviceaccording to an embodiment is provided, including a RF receiving circuit11, a storage capacitor 12, and a crystal oscillator circuit 13. The RFreceiving circuit 11 receives an energy feedback RF signal from anenergy feedback device and converts the RF signal to electric energy.The electric energy is stored into/in the storage capacitor 12. Afterthe voltage of the storage capacitor 12 reaches a suitable level, thecrystal oscillator circuit 13 starts to transmit a RF signal under thecurrent temperature to an external receiving and processing device. Thesuitable level of the voltage of the storage capacitor 12 means that,the voltage of the storage capacitor 12 is enough for the crystaloscillator to work for a predetermined period. Different storagecapacitors with different storage capacities can be used according todifferent requirements. The crystal oscillator circuit 13 can be aceramic crystal oscillator circuit or a quartz crystal oscillatorcircuit. The wireless and passive temperature sensing device isconfigured without a structure for being connected to an external powersupply and without space for receiving a battery, thus, the wireless andpassive temperature sensing device can have a relatively small size forhaving less components, making the device be small and portable. Thisallows the user to place the wireless and passive temperature sensingdevice on any position such as on the underwear, pants, or the armpitsince the wireless and passive temperature sensing device may not affectdaily life of the user, which improves the temperature measuringexperience of the wireless and passive temperature sensing device.

In some embodiments, the withstand voltage of the storage capacitor 12is 2.7 V, and the capacitance of the storage capacitor 12 is 2200 uF.The storage capacitor is environmental-friendly and safe, and thequantity of electricity stored in the storage capacitor 12 is enough forthe crystal oscillator circuit to work for more than 100 milliseconds.

Referring to FIG. 3, the wireless and passive temperature sensing devicefurther includes a first house 1. The RF receiving circuit 11, thestorage capacitor 12, and the crystal oscillator circuit 13 areconfigured in the first house 1. One side of the first house 1corresponding to the crystal oscillator circuit 13 is made of thermalconductive material, which ensures that the crystal oscillator 13 iscapable of sensing the temperature more quickly and the temperature iscloser to the real value. Alternatively, the side of the house 1corresponding to the crystal oscillator 13 can form an opening 101through which the crystal oscillator circuit 13 protrudes from the sideof the house 1. At least one protrusion 102 is configured on theperipheral side of the house 1. A through hole 103 is defined in eachprotrusion 102. The configuration of the protrusion 102 and the throughhole 103 allows the wireless and passive temperature sensing device tobe secured to the underwear or the pants of the user. In someembodiments, Velcro can be configured on the first house 1 such that thedevice can be directly pasted to the underwear or pants of the user. Inother embodiments, a locking component such as a fastener can beconfigured on the first house 1 to be connected to the opening formed inthe underwear or pants of the user, thus the device can be secured tothe underwear or pants of the user by using a fastener.

Referring to FIG. 4, an energy feedback device according to anembodiment is provided, including a temperature compensation crystaloscillator 21 and a RF power amplifier 22. A RF signal from thetemperature compensation crystal oscillator 21 is amplified by the RFpower amplifier 22 and is further transmit to the wireless and passivetemperature sensing device. The energy feedback device may furtherinclude other supplementary components such as a power supply. Theenergy feedback device generates the RF signal having a specialfrequency through the temperature compensation crystal oscillator 21which is transmit to the wireless and passive temperature sensing deviceafter being amplified by the RF power amplifier, thus, the wireless andpassive temperature sensing device can obtain enough energy requiringfor starting up. Furthermore, the energy feedback device and thetemperature sensing device are wirelessly connected, which isconvenient.

Referring to FIG. 5, a receiving and processing device according to anembodiment is provided, including a temperature compensation crystaloscillator 31, a RF receiving amplifier 32, and a signal processor 33.The RF receiving amplifier 32 receives the RF signal under the currenttemperature from the wireless and passive temperature sensing device andoutputs the RF signal to the signal processor 33. The signal processor33 calculates the current temperature according to the inherentfrequency of the temperature compensation crystal oscillator 31 and thereceived RF signal under the current temperature. Since the resonantfrequency of the temperature compensation crystal oscillator 31 isfixed, by comparing the resonant frequency of the temperaturecompensation crystal oscillator 31 with the frequency of the RF signalsent from the crystal oscillator circuit of the wireless and passivetemperature sensing device, the signal processor 33 can analyze thetemperature information contained in the offset of the frequency of theRF signal sent from the crystal oscillator circuit, to obtain thecurrent temperature. The temperature can be calculated according to thefollowing method: the signal processor 33 is provided with a data listcontaining different temperatures corresponding to different frequencyoffsets; when a frequency offset is analyzed, looking up thecorresponding temperature directly in the data list. For example, thefrequency of the temperature compensation crystal oscillator 31 of thereceiving and processing device is 100 MHZ, and the frequency of the RFsignal output thereby is always 100 MHZ, which remains unchanged withtemperature; the frequency of the RF signal sent from the wireless andpassive temperature sensing device is also 100 MHZ; however, withouttemperature compensation, the frequency of the RF signal from thewireless and passive temperature sensing device may change 50 HZ whilethe temperature changes 1° C. For example, if the frequency of the RFsignal is 100000000 HZ when the temperature is 24° C., then thefrequency would be 100000050 HZ when the temperature is 25° C. and wouldbe 100000100 HZ when the temperature is 26° C., and so on. Thus, thecurrent temperature can be obtained according to the frequency of the RFsignal from the wireless and passive temperature sensing device.

In some embodiments, the receiving and processing device may furtherinclude a network unit connected to the signal processor 33 forreceiving and transmitting data through network. The calculatedtemperature can be sent to other users who are not present during themeasurement through network. For example, in the hospital, the nurse orthe patient can send the measured temperature to the doctor throughnetwork, allowing the doctor to obtain the temperature features of thepatient, which is convenient and fast.

Referring to FIG. 6, an energy feedback receiving and processing deviceaccording to an embodiment is provided, including a temperaturecompensation crystal oscillator 41, a RF power amplifier 22, a RFreceiving amplifier 32, and a signal processor 33. The RF signal fromthe temperature compensation crystal oscillator 41 is amplified by theRF power amplifier 22 and is further transmit to the wireless andpassive temperature sensing device. The RF receiving amplifier 32receives the RF signal under the current temperature sent from thewireless and passive temperature sensing device and outputs the signalto the signal processor 33. The signal processor 33 calculates thecurrent temperature according to the inherent frequency of thetemperature compensation crystal oscillator 41 and the received RFsignal. The difference between the integration of the receiving andprocessing device and the energy feedback device provided in the aboveembodiment and the energy feedback receiving and processing deviceprovided in the embodiment lies in that, the integration of thereceiving and processing device and the energy feedback device includestwo temperature compensation crystal oscillators 21 and 31, while theenergy feedback receiving and processing device only includes onetemperature compensation crystal oscillator 41. The temperaturecompensation crystal oscillator 41 provides the energy feedback RFsignal having a special frequency as well as the frequency required bythe signal processor 33.

In some embodiments, the energy feedback receiving and processing devicefurther includes a second house. The temperature compensation crystaloscillator 41, the RF power amplifier 22, the RF receiving amplifier 32,and the signal processor 33 are configured in the second house to be anintegration one which can be conveniently used and prevents somecomponent from being lost easily.

Referring to FIG. 7, a system for wirelessly and passively measuringtemperature is provided according to an embodiment, including a wirelessand passive temperature sensing device 10, an energy feedback device 20,and a receiving and processing device 30.

The energy feedback device 20 includes a temperature compensationcrystal oscillator 21 and a RF power amplifier 22. A RF signal from thetemperature compensation crystal oscillator 21 is amplified by the RFpower amplifier 22 and is further transmit to the wireless and passivetemperature sensing device 10.

The wireless and passive temperature sensing device 10 includes a RFreceiving circuit 11, a storage capacitor 12, and a crystal oscillatorcircuit 13. The RF receiving circuit 22 receives an energy feedback RFsignal from the energy feedback device 10 and converts the RF signal toelectric energy. The electric energy is stored into/in the storagecapacitor 12. After the voltage of the storage capacitor 12 reaches asuitable level, the crystal oscillator circuit 13 is activated totransmit a RF signal under the current temperature to the receiving andprocessing device 30. The wireless and passive temperature sensingdevice 10 is configured without a structure for being connected to anexternal power supply and without space for receiving a battery, thus,the device can have a relatively small size for having less components,making the device be small and portable. This allows the user to placethe device on any position such as on the underwear, pants, or thearmpit since the device may not affect daily life of the user, whichimproves the temperature measuring experience of the system.

The receiving and processing device 30 includes a temperaturecompensation oscillator 31, a RF receiving amplifier 32, and a signalprocessor 33. The RF receiving amplifier 32 receives the RF signal underthe current temperature sent from the wireless and passive temperaturemeasuring device 10 and outputs the signal to the signal processor 33.The signal processor calculates the current temperature according to theinherent frequency of the temperature compensation crystal oscillator 31and the RF signal under the current temperature. Since the resonantfrequency of the temperature compensation crystal oscillator 31 isfixed, by comparing the resonant frequency of the temperaturecompensation crystal oscillator 31 with the frequency of the RF signalsent from the crystal oscillator circuit of the wireless and passivetemperature sensing device, the signal processor 33 can analyze thetemperature information contained in the offset of the frequency of theRF signal sent from the crystal oscillator circuit, to obtain thecurrent temperature. The temperature can be calculated according to thefollowing method: the signal processor 33 is provided with a data listcontaining different temperatures corresponding to different frequencyoffsets; when a frequency offset is analyzed, looking up thecorresponding temperature directly in the data list.

In some embodiments, the withstand voltage of the storage capacitor 12of the wireless and passive temperature sensing device 10 is 2.7 V, andthe capacitance of the storage capacitor 12 is 2200 uF. The storagecapacitor is environmental-friendly and safe, and the dischargingprocess of the storage capacitor 12 can last for more than 100milliseconds.

In some embodiments, the wireless and passive temperature sensing devicefurther includes a first house 1. The RF receiving circuit 11, thestorage capacitor 12, and the crystal oscillator 13 are configured inthe first house 1. One side of the first house 1 corresponding to thecrystal oscillator circuit 13 is made of thermal conductive material,which ensures that the crystal oscillator 13 receives the temperaturemore quickly and the temperature is closer to the real value.Alternatively, the side of the house 1 corresponding to the crystaloscillator 13 can form an opening 101 through which the crystaloscillator circuit 13 protrudes from the side of the house 1. At leastone protrusion 102 is configured on the peripheral side of the house 1.A through hole 103 is defined in each protrusion 102. The configurationof the protrusion 102 and the through hole 103 allows the device to besecured to the underwear or the pants of the user.

In some embodiments, the receiving and processing device 30 may furtherinclude a network unit connected to the signal processor 33 forreceiving and transmitting data through network. The calculatedtemperature can be sent to other users who are not present during themeasurement through network. For example, in the hospital, the nurse orthe patient can send the measured temperature to the doctor throughnetwork, allowing the doctor to obtain the temperature features of thepatient, which is convenient and fast.

Referring to FIG. 8, a system for wirelessly and passively measuringtemperature according to another embodiment is provided, including awireless and passive temperature sensing device 10 and an energyfeedback receiving and processing device 40.

As shown in FIG. 2, the wireless and passive temperature sensing device10 includes a RF receiving circuit 11, a storage capacitor 12, and acrystal oscillator circuit 13. The RF receiving circuit 11 receives anenergy feedback RF signal from an energy feedback device, and convertsthe RF signal to electric energy. The electric energy is stored into/inthe storage capacitor 12. After the storage capacitor 12 is conducted,the crystal oscillator circuit 13 is activated to transmit a RF signalunder the current temperature to the energy feedback receiving andprocessing device. The wireless and passive temperature sensing deviceis configured without a structure for being connected to an externalpower supply and without space for receiving a battery, thus, the devicecan have a relatively small size for having less components to be smalland portable. This allows the user to place the device on any positionsuch as on the underwear, pants, or the armpit since the device may notaffect daily life of the user, which improves the temperature measuringexperience of the system.

As shown in FIG. 6, the energy feedback receiving and processing device40 includes a temperature compensation crystal oscillator 41, a RF poweramplifier 22, a RF receiving amplifier 32, and a signal processor 33.The RF signal from the temperature compensation crystal oscillator 41 isamplified by the RF power amplifier 22 and is further transmit to thewireless and passive temperature sensing device. The RF receivingamplifier 32 receives the RF signal under the current temperature fromthe wireless and passive temperature sensing device and outputs the RFsignal to the signal processor 33. The signal processor 33 calculatesthe current temperature according to the inherent frequency of thetemperature compensation crystal oscillator 41 and the received RFsignal. The difference between the integration of the receiving andprocessing device and the energy feedback device provided in the aboveembodiment and the energy feedback receiving and processing deviceprovided in the embodiment lies in that, the integration of thereceiving and processing device and the energy feedback device includestwo temperature crystal oscillators 21 and 31, while the energy feedbackreceiving and processing device only includes one temperature crystaloscillator 41. The temperature compensation crystal oscillator 41provides the energy feedback RF signal having a special frequency aswell as the frequency required by the signal processor 33.

The energy feedback receiving and processing device 40 may furtherinclude a network unit connected to the signal processor for receivingand transmitting data through network. Thus, the calculated temperaturecan be sent to other users who are not present during the measurementthrough network. For example, in the hospital, the nurse or the patientcan send the measured temperature to the doctor through network,allowing the doctor to obtain the temperature features of the patient,which is convenient and fast.

In the above different embodiments, different codes are set tocorrespond to different wireless and passive temperature sensing devicesto represent different users. The receiving and processing device cansimultaneously receive signal data from multiple wireless and passivetemperature sensing devices. Furthermore, a timer can be disposed insidethe energy feedback device, such that the energy feedback device cantransmit energy at given time and the wireless and passive temperaturesensing device can be started to transmit the RF signal under thecurrent temperature.

In one case, the system for wirelessly and passively measuringtemperature as shown in FIG. 7 can be used as follows: the user carriesthe wireless and passive temperature sensing device 10 secured to theunderwear or pants, and the crystal oscillator of the crystal oscillatorcircuit of the device 10 is in contact with the skin of the user; whenmeasuring the body temperature, the energy feedback device 20 work in ashort period to transmit the energy feedback RF signal; the receivingand processing device 30 is started to receive the RF signal under thecurrent temperature sent from the device 10 for analysis; beforereceiving the RF signal under current temperature sent from the device10, the receiving and processing device 30 keeps detecting the RFsignal; and after receiving the RF signal under the current temperature,the receiving and processing device 30 accurately measures the frequencyoffset of the RF signal using frequency mixing and frequencydiscrimination technology and calculates the temperature correspondingto the frequency offset to obtain the user's body temperature, which isconvenient and fast. With the system for wirelessly and passivelymeasuring temperature, the user can get new temperature measurementexperience and finish the measurement of the body temperature by storingand uploading the measured temperature.

In the above process, since the wireless and passive temperature sensingdevice 10 can work for 100 milliseconds, and the receiving and processdevice 30 can be started after the energy feedback device 20 is startedto save the frequency resource.

In the above embodiment, the wireless and passive temperature sensingdevice 10 can be configured with supplementary device such as RFID tofinish the temperature measurement better.

The description of the disclosed embodiments is provided to illustratethe present invention to those skilled in the art. Various modificationsto these embodiments will be readily apparent to those skilled in theart, and the generic principles defined herein may be applied to otherembodiments without departing from the spirit or scope of the invention.Thus, the present invention is not intended to be limited to theembodiments shown herein but is to be accorded the widest scopeconsistent with the principles and novel features disclosed herein.

What is claimed is:
 1. A method for wirelessly and passively measuringtemperature, comprising: receiving an energy feedback radio frequency(RF) signal by a temperature measuring end; converting the energyfeedback RF signal into electric energy and storing the electric energy;and starting the temperature measuring end after obtaining the electricenergy, transmitting a RF signal under the current temperature to aterminal, and calculating the current temperature through the terminal.2. The method according to claim 1, wherein the temperature measuringend comprises a crystal oscillator circuit; the crystal oscillatorcircuit starts after obtaining the electric energy, and transmits the RFsignal under the current temperature.
 3. The method according to claim1, wherein the step of converting the energy feedback RF signal intoelectric energy and storing the electric energy comprises: receiving theenergy feedback RF signal through a RF receiving circuit by thetemperature measuring end, and storing the energy of the feedback RFsignal into a storage capacitor by the RF receiving circuit.
 4. Themethod according to claim 1, wherein after the step of starting thetemperature measuring end after obtaining the electric energy, andtransmitting a RF signal under the current temperature to a terminal,and calculating the current temperature through the terminal, the methodfurther comprises: sending the calculated current temperature to aremote terminal through network.